Logistical constraints

This study evaluates an accelerated schedule of theta-burst stimulation using a transcranial magnetic stimulation device for treatment-resistant depression. In a double-blind fashion, half the participants will receive accelerated theta-burst stimulation while half will receive sham treatment.

Repetitive transcranial magnetic stimulation (rTMS) is an established technology as therapy for treatment-resistant depression. The approved method for treatment is 10Hz stimulation for 40 min over the left dorsolateral prefrontal cortex (L-DLPFC). This methodology has been effective in real world situations. The limitations of this approach include the duration of the treatment (approximately 40 minutes per treatment session, 5 days per week, for 4-8 weeks). Recently, researchers have pursued modifying the treatment parameters to reduce treatment times with some preliminary successes. This study aims to further modify the parameters to create a more rapid form of the treatment and look at the change in neuroimaging biomarkers.

Inclusion Criteria:

• Male or female, 22 to 80 years of age.
• Able to provide informed consent.
• Diagnosed with Major Depressive Disorder (MDD) and currently experiencing a Major Depressive Episode (MDE).
• Participants may currently be on a stable and adequate dose of SSRI antidepressant therapy. Participants may choose to not be on antidepressant therapy for the study duration, or to be switched from other classes to a medication from the SSRI class.
• Participants may also have a history of intolerance to at least 2 antidepressant medications. These patients with the intolerance history will not be required to be currently taking an antidepressant medication.
• Participants must qualify as "Moderately Treatment Refractory" or "High Treatment Refractory" using the Maudsley staging method.
• Meet the threshold on the total HAMD17 score of >/=20 at both screening and baseline visits (Day -5/-14 and Day 0).
• Meet the threshold on the total MADRS score of >/=20 at both screening and baseline visits (Day -5/-14 and Day 0).
• Meet the threshold on the total BDI-II score of >/=20 at both screening and baseline visits (Day -5/-14 and Day 0).
• In good general health, as ascertained by medical history.
• If female, a status of non-childbearing potential or use of an acceptable form of birth control. The form of birth control will be documented at screening and baseline.
• Concurrent hypnotic therapy (e.g., with zolpidem, zaleplon, melatonin, or trazodone) will be allowed if the therapy has been stable for at least 4 weeks prior to screening and if it is expected to remain stable.

Exclusion Criteria:

• Female of childbearing potential who is not willing to use one of the specified forms of birth control during the study.
• Female that is pregnant or breastfeeding.
• Female with a positive pregnancy test at participation.
• Total HAMD17 score of < 20 at the screen or baseline visits.
• Total MADRS score of < 20 at the screen or baseline visits.
• Total BDI-II score of < 20 at the screen or baseline visits.
• Current diagnosis of a Substance Use Disorder (Abuse or Dependence, as defined by DSM-IV-TR), with the exception of nicotine dependence, at screening or within six months prior to screening.
• Current diagnosis of Axis I disorders other than Dysthymic Disorder, Generalized Anxiety Disorder, Social Anxiety Disorder, Panic Disorder, Agoraphobia, or Specific Phobia (unless one of these is comorbid and clinically unstable, and/or the focus of the participant's treatment for the past six months or more).
• History of schizophrenia or schizoaffective disorders, or any history of psychotic symptoms in the current or previous depressive episodes.
• Any Axis I or Axis II Disorder, which at screening is clinically predominant to their MDD or has been predominant to their MDD at any time within six months prior to screening.
• Considered at significant risk for suicide during the course of the study.
• Has a clinically significant abnormality on the screening examination that might affect safety, study participation, or confound interpretation of study results.
• Participation in any clinical trial with an investigational drug or device within the past month or concurrent to study participation.
• Any current or past history of any physical condition which in the investigator's opinion might put the subject at risk or interfere with study results interpretation.
• History of positive screening urine test for drugs of abuse at screening: cocaine, amphetamines, barbiturates, opiates.
• Current (or chronic) use of opiates.
• History of epilepsy.
• History of rTMS exposure.
• History of any implanted device or psychosurgery for depression.
• History of ECT intolerance.
• History of shrapnel or metal in the head or skull.
• "Low Treatment Refractory" using the Maudsley staging method.
• History of cardiovascular disease or cardiac event.
• History of OCD.
• History of autism spectrum disorder.
• History of intractable migraine
• History of independent sleep disorder.